Lubricant



Patented May 20, 1947 LUBRICANT Russell A. Hunt, Jr., Hammond, Ind.,assignor to Standard Oil Company, Chicago, 111., a corporation ofIndiana No Drawing. Application August 19, 1944, Serial No. 550,305

Claims.

This invention relates to improvements in lubricants and morespecifically to improvements in lubricants which come in contact withcopper surfaces such as ice machine lubricants.

In the lubrication of certain types of machinery in which the lubricantcomes in contact with copper parts of such equipment, it has beenobserved that a phenomenon known as copper plating takes place. Thisphenomenon occurs particularly in the lubrication of-refrigerators orice machines. In the lubrication of such equipment the oil employedcomes in contact with the copper coils and other parts of the equipmentin which copper is employed. Copper plating of the nature hereinreferred to is the phenomenon in which copper is removed from certainparts of the equipment and deposited in other parts thereof; Thus inrefrigeration systems, for example, copper is removed from elements suchas the copper tubing and deposited on the parts of the system which areformed of some metal other than copper or its alloy such as the steel orother ferrous metal parts of the equipment. Usually the deposit ofcopper takes place on moving parts of the system such as on pistonsand/or valves and results frequently in serious interference inoperation of the machinery. This phenomenon of copper plating isassociated with and amylenes.

the lubricating oil employed for the lubrication of moving parts of suchequipment. The reason for this copper plating is not completelyunderstood. However, the fact remains that it does occur even thoughhighly refined lubricating oils are usually employed in the lubricationof such equipment.

It is therefore an object of this invention to provide a lubricant whichwill prevent copper plating in equipment in which such lubricanttisemployed. Another object of the present invention is to provide animproved refrigerator lubricant which will prevent copper plating.

Still another object of the invention is to provide a method ofpreventing copper plating in the lubrication of equipment in whichcopper or copper alloys are employed.-

I have discovered that the foregoing objects can be attained bylubricating systems in which copper and/or copper alloys are employedwith a highly refined hydrocarbon oil, particularly a synthetichydrocarbon oil containing small amounts of a copper deactivator andpreferably a phenyl-alpha-naphthylamine.

While the present invention is applicable to any highly refinedhydrocarbon oil which is susceptible to copper plating, it isparticularly applicable to synthetic hydrocarbon oils, and especially toa mono-olefin polymer having a Saybolt Universal viscosity at F. of fromabout 50 seconds to about 400 seconds or higher depending upon the typeof equipment to be lubricated. This synthetic oil is preferably anolefin hydrocarbon polymer resulting from the polymerization of lowmolecular weight mono-oleflnic hydrocarbons or isomono-olefinichydrocarbons or mixtures thereof such as propylene, butylenes Thesepolymers or copolymers can be obtained by the polymerization of theseolefins or mixtures of olefins in the presence of a catalyst such assulfuric acid, phosphoric acid. boron fluoride, aluminum chloride orsimilar halide catalysts of the Friedel-Crafts type. A suitablesynthetic oil is one obtained by polymerizing in the liquid phase ahydrocarbon mixture containing mono-olefins and iso-olefins such asbutylene and isobutylene at a temperature of from about 50 F. to about100 F. in the presence of a metal halide catalyst of the Friedel-Craftsty such as, for example, boron fluoride,- alu- I minum chloride and thelike. A suitable source of low molecular weight olefinic hydrocarbonssuitable for this purpose is a hydrocarbon mixture containingisobutylene, butylene and butanes recovered from petroleum gases,especially those gases produced in the cracking of petroleum oils in themanufacture of gasoline.

Another suitable polymer is that obtained by polymerizing at atemperature of from about 50 F. to about F. in theliquid phase ahydrocarbon mixture comprising substantially C: bydrocarbons in thepresence of an aluminum chloride complex catalyst. The catalyst ispreferably prepared by heating aluminum chloride with iso-octane. Thepropylene polymer so obtained con be fractionated to obtain a fractionhaving the desired viscosity range.

Suitable copper deactivators whichvcan'beem ployed in the presentinvention are the reaction products of aromatic ortho hydroxyaldehyde's, such as 2-hydroxybenzaldehyde, 2-4-dihydroxybenzaldehyde, 2hydroxy 3 methoxybenzaldephenyl-alpha-naphthylamine.

hyde, etc. with polyamines, particularly an allphatic polyaminecontaining at least two primary amino nitrogen atoms, such asmethylenediamine, ethylene diamine, diethylene trlamine, 1-10- decylenediamine, triethylene tetramine, propylene diamine, tetraethylenepentamine, etc. Suitable copper deactivators also are those obtained byreacting an ortho hydoxy aromatic ketone with an aliphatic polyaminecontaining at least two primary amino groups. Specific examples of suchcompounds are di-Z-hydroxy acetophenone ethylene diamine, di-z-hydroxypropiophenone ethylene diamine, di-2-hydroxy-5-methylacetophenone 1,3propylene diamine, etc. Other copper deactivators which can be employedin the present invention are the reaction products of diacyl compoundsand primary amines such as dibenzoyl acetonyl ethylene diamine anddiacetyl acetonyl ethylene diamine; hydroxy aromatic aldoximes andketoximes such as ortho hydroxybenzaldoxlme, orthohydroxyacetophenoxime, etc. While compounds of the foregoing type areall active metal deactivators, particularly copper deactivators, theyall are not equally effective. The copper deactivator can be employed inamounts of from about 0.001% to about 2% and preferably from about0.005% to about 0.05%.

In addition to the metal deaztivator, the lubricant composition of thepresent invention preferably also contains a small amountname1y, fromabout 0.001% to about 2% and preferably from about 0.01% to about 0.5 ofa phenylalpha-naphthylamine.

'When desired the lubricant can contain other additives such as, forexample, from about 0.5% to about 3% of a film strengthening additive,e. g. tricresyl phosphate and the like.

In order that the present invention may be more fully appreciated andunderstood, the same will be described in connection with an ice ma-'chine oil composition although it is to be understood that this is givenmerely by way of illustration and not to be construed as a limitationupon the scope of the present invention. An ice maJhine oil comprising abutylene polymer having a Saybolt Universal viscosity at 100 F. of about50 seconds was compounded with 0.02% of a copper deactivator obtained byreacting salicylal with a polyamine and 0.01% ofphenylalpha-naphthylamlne. The ice machine oil also contained inaddition to the aforementioned additives 1% of tricresyl phosphate toincrease the film strength of the oil. The resistance to copper platingof this oil was compared with the resistance to copper plating of thesame butylene .polymer containing only the copper deactivator andanother sample of the oil containing only In determining the resistanceto copper plating or the copper susceptibility of the various oils 25cc. of the oil to'be tested in contact with 6 /2 feet of clean,- bright,No. 18 gauge copper wire is heated at 200 F. A sample of oil is thenmixed with an equal portion of diphenylthiocarbazone (dithizone)solution to determine the presence of cop: per in the solution, a purplecolor indicating that copper is present. Samples of the oil are taken,tested at 2 hours, 6 hours and 24 hours and every 24 hours thereafteruntil a positive copper test is obtained. The copper life" is the timerequired for a positive copper test by this 4 solving 50 mg. ofdiphenylthiocarbazone in one liter of carbon tetrachloride. Since thedithizone reagent is extremely sensitive to light, the reagent'must bekept in a dark bottle under refrigeration. The efiect of the copperdeactivator in preventing copper plating is demonstrated by the data inTable I. The synergistic efiect of the combination of a metaldeactivator and a phenyl-alpha-naphthylamine is illustrated by thefollowing copper susceptibility data in Table Table I Hours to showPositive Copper Test Oil Additive Butylenepolymer None Do. 1.0%tricresyl phosphate. D01 0.02% copper deactivate: None 0.02% copperdeactivate! +10% tricrcsyl phosphate. None 0.02% copper deactivntor +10%tricrcsyl phosphute. None 0.02% copper deactivate:-

+10% tricresyl phosphate.

I Table II Hours to show Positive Copper Test Oil Additive Butylenepolymer a -l Oi KING 1 Saybolt Universal viscosity at F.=50 secs.

1 Saybolt Universal viscosity at 100 F.=i00 secs.

1 Saybolt Universal viscosity at 100 F.=200 secs.

Saybolt Universal viscosity at 100 F.=400 secs.

5 Reaction product of salicylal and triethylene tetmmine.

To facilitate solution of the additives in the hydrozarbon oil, it isfrequently advisable to incorporate the additives in the oil in thepresence of an aromatic solvent. A suitable solvent for this purpose isa fraction high in aromatics obtained by the catalytic conversion oipetroleum naphtha in the presence of a dehydrogenating catalyst andpreferably in the presence of hydrogen. The product of this conversionis a mixture of reformed naphtha suitable for gasoline of high knockrating and heavier hydrocarbons boiling largely above the boiling pointof the naphtha charged. This reaction product boiling within the rangeof about 425 F. to about 600 F. is high in aromatics and contains liquidderivatives of naphthalene. This fraction is known as hydroformerbottoms. While I prefer to use these hydroformer bottoms as the solventin the preparation of the herein-described lubricants, other suitablesolvents can, of course, be used.

While I have described my invention with particular reference torefrigerator or ice machine lubricants, it is to be understood that theinvention is not limited to this particular type of lubricant but isapplicable to any lubricant susceptible to cause copper plating whenused in the presence of copper or copper alloys.

Iclaim:

1. A hydrocarbon oil composition resistant to copper plating comprisinga hydrocarbonoil normally susceptible to cause copper plating in thepresence of a copper-containing metal, a copper deactivator andtricresyl phosphate, said copper deactivator and said tricresylphosphate being used in small but suificent quantities to inhibit thecopper plating by said hydrocarbon oil said copper deactivator being thereaction product of an aliphatic polyamino compound having at least twoprimary amino nitrogen atoms and an arcmatic compound selected from theclass consisting of aromatic ortho hydroxy aldehydes and ortho hydroxyaromatic ketones.

2. A hydrocarbon oil composition as described in claim 1 in which fromabout 0.001% to about 2% of the copper deactivator and from about 0.5%to about 3% of the tricresyl phosphate are employed.

3. A hydrocarbon oil composition as described in claim 1 containing fromabout 0.01% to about 0.5% of a phenyl alpha-naphthylamine.

4. A hydrocarbon oil composition as described in claim 1 in which themetal deactivator is the reaction product of an aromatic ortho hydroxyaldehyde and an aliphatic polyamine compound having at least two primaryamino nitrogen atoms.

5. A hydrocarbon oil composition as described in claim 1 in which thecopper deactivator is the reaction product of ortho hydroxy benzaldehydeand an aliphatic amine having at least two primary amino nitrogen atoms.

6. A hydrocarbon oil composition as described in claim 1 in which thecopper deactivator is the reaction product of an ortho hydroxy aromaticketone and an aliphatic polyamine containing at least two primary aminonitrogen atoms.

7. A hydrocarbon oil composition which does not cause copper plating inthe presence of a copper-containing metal comprising a synthetichydrocarbon oil obtained by the polymerization of monoolefins, and whichnormally is susceptible to cause copper plating in the presence of acoppercontaining metal, a copper deactivator and tricresyl phosphate,said copper deactivator and said tricresyl phosphate being used in smallbut suflicient quantities to inhibit the copper plating by saidsynthetic hydrocarbon oil, and said copper deactivator being thereaction product of an aliphatic polyamino compound having at least twoprimary amino nitrogen atoms and an aromatic compound selected from theclass consisting of aromatic ortho hydroxy aldehydes and ortho hydroxyaromatic ketones.

8. A hydrocarbon oil composition as described in claim 5 in which thesynthetic hydrocarbon oil is a butylene polymer having a SayboltUniversal viscosity at 100 F. of from about 50 seconds to about 400seconds.

9. A hydrocarbon oil composition as described in claim 5 in which thesynthetic hydrocarbon oil is a propylene polymer having a SayboltUniversal viscosity at 100 F. of from about 50 seconds to about 400seconds.

10. A hydrocarbon oil-composition as described in claim 5 in which themetal deactivator is the reaction product or an aromatic ortho hydroxyaldehyde and a polyamino compound having at least four nitrogen atoms ofwhich at least two are primary amino nitrogen atoms.

11. A hydrocarbon oil composition as described in claim 5 in which thecopper deactivator is the reaction product of ortho hydroxy benzaldehydeand an alkylene amine having at least four nitrogen atoms of which atleast two are primary amino nitrogen atoms.

12. A hydrocarbon oil composition as described in claim 5 in which thecopper deactivator is the reaction product of an ortho hydroxy aromaticketone and an aliphatic polyamine containing at least two primary aminonitrogen atoms.

13. A hydrocarbon oil composition which does not cause copper plating inthe presence of a copper-containing metal comprising a mono-olefinpolymer oil having a Saybolt Universal viscosity at F. of from about 50seconds to about 400 seconds and normally susceptible to cause copperplating in the presence of copper-containing metal, from about 0.005% toabout 0.05% of the reaction product of ortho hydroxy benzaldehyde and analiphatic polyamine containing at least two primary amino nitrogenatoms, from about 0.01% to about 0.5% of a phenyl-alphanaphthylamine andfrom about 0.5% to about 3% of tricresyl phosphate.

14. The method of preventing copper plating in a system containingcopper-containing metal lubricated with a hydrocarbon oil comprisinglubrieating said system with a hydrocarbon oil composition comprising ahydrocarbon oil normally susceptible to cause plating in the presence ofa copper-containing metal, a copper deactivator and tricresyl phosphatein small but sufiicient quantities to substantially inhibit copperplating of said hydrocarbon oil said copper deactivator being thereaction product of an aliphatic polyamino compound having at least twoprimary amino nitrogen atoms and an aromatic compound selected from theclass consisting ofaromatic ortho hydroxy aldehydes and ortho hydroxyaromatic ketones.

15. The method described in claim 12 in which the hydrocarbon oil is amono-olefin polymer oil having a Saybolt Universal viscosity at 100 F.of from about 50 seconds to about 400 seconds and which is normallysusceptible to cause copper plating in the presence of acopper-containing metal and in which the copper deactivator is areaction product of an aromatic ortho hydroxy aldehyde and an aliphaticpolyamine containing at least two primary amino nitrogen atoms.

RUSSELL A. HUNT, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

